Charge Storage Component for Power IGFET Ringing Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Power insulated-gate field-effect transistors (IGFETs) suffer from ringing due to interactions between package inductance and circuit board non-linear output capacitance, exacerbated by faster switching speeds and lower on-state resistance, which existing integrated snubber structures fail to adequately address.
Innovation Solution
The design incorporates a resistance-capacitor (RC) structure with a substrate featuring a buried conductive region, semiconductor region, and trenches to create a bi-modal capacitance-voltage characteristic, reducing ringing by allowing capacitance to fall rapidly during switching transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If faster switching speeds and lower on-state resistance are implemented in power IGFETs, then efficiency is improved, but ringing is aggravated due to interaction with package inductance and non-linear output capacitance
Solution Approach 1:
The patent converts the harmful non-linear output capacitance effect into a beneficial bi-modal capacitance-voltage characteristic by integrating a charge storage component (PNP transistor with stored charge) that provides controlled capacitance behavior. The stored charge in the collector-base junction creates a pseudo-capacitance that counteracts the parasitic inductance, transforming the previously harmful ringing effect into a damping mechanism that suppresses oscillations while maintaining fast switching performance.
Solution Approach 2:
The patent merges the charge storage component directly into the transistor structure by integrating the PNP transistor within the N-channel IGFET device. The collector-base junction of the PNP transistor is formed using the same semiconductor regions (body region and drain region) of the N-channel transistor, eliminating the need for separate external snubber components and reducing package inductance while providing the required capacitance-voltage characteristics.
2Object-generated harmful factors
If existing integrated snubber structures are used, then some ringing suppression is achieved, but they are insufficient to keep pace with advances in newer power IGFET technologies
Solution Approach 1:
The patent changes the fundamental parameter of capacitance behavior from fixed or linear to bi-modal and non-linear by utilizing the charge storage mechanism in the PNP transistor. The stored charge creates a voltage-dependent capacitance that dynamically adapts to different operating conditions, providing effective ringing suppression across a wide range of switching speeds and voltage levels that accommodate newer power IGFET technologies.
Solution Approach 2:
The charge storage component utilizes the existing charge carriers in the collector-base junction of the integrated PNP transistor, eliminating the need for external snubber components. The stored charge automatically provides the necessary capacitance effect during switching transitions, making the device self-sufficient and adaptable to various power IGFET technologies without requiring external passive components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces or eliminates ringing associated with switching in power transistors, maintaining performance without requiring additional masks or process steps beyond existing flows.
Implementation Method 1
a charge storage component can include a first electrode and a second electrode. The first electrode can include the pillar, and the second electrode can include the conductive member
Data Source
AI summary
A circuit and physical structure can help to counteract non-linear COSS associated with power transistors that operate at higher switching speeds and lower RDSON. In an embodiment, a component with a pn junction can be coupled to an n-channel IGFET. The component can include a p-channel IGFET, a pnp bipolar transistor, or both. A gate/capacitor electrode can be within a trench that is adjacent to the active regions of the component and n-channel IGFET, where the active regions can be within a semiconductor pillar. The combination of a conductive member and the semiconductor pillar of the component can be a charge storage component. The physical structure may include a compensation region, a barrier doped region, or both. In a particular embodiment, doped surface regions can be coupled to a buried conductive region without the use of a topside interconnect or a deep collector type of structure.